Method for controlling subscriber station power in code-division communication system

FIELD: communication systems.

SUBSTANCE: proposed method includes dynamic control of subscriber station transmitter considering noise level in vicinity of base station location and information load on base station by estimating quality of communication channel and accounting for network subscriber priority.

EFFECT: enhanced reliability of mobile communication system.

1 cl, 2 dwg

 

This invention relates to communication systems and, in particular, ways to control the transmit power of the subscriber stations in the mobile cellular code division of channels.

Known methods of controlling the transmit power of the subscriber stations (see U.S. patent US No. 4901307, 04J 13/00, 1990; US No. 5056109 04L 27/30, 1991).

In the known methods control the transmit power of the subscriber station is performed on the measured power level of the signal received from the base station. Measure the power level of the signal at the receiving subscriber station (MSS) and taking into account the level of transmit power of a base station (BS) on-line communication base station is a subscriber station and the sensitivity of the receiver in the subscriber station, the subscriber transceiver station calculates losses on the road in the transmission channel between it and the base station. Next, the transceiver of the subscriber station determines the appropriate transmit power required for transmitting signals between the subscriber station and the base station based on the measured path loss, data rate and receiver sensitivity of the base station, change the transmit power of the subscriber station.

A disadvantage of the known ways to control the transmit power of the subscriber station is that they do not take into account the use of the separate frequency ranges, which is of great importance when managing power transmitters subscriber stations. The use of separate frequency ranges is the reason that the attenuation and fading into the receiving and transmitting paths are independent of each other. The subscriber station cannot simply be measured path loss in the transmitting tract relative to the BS (path BS-AC) and take the same value as path loss in the receiving path relative to the BS (path AC-BS).

The closest to the technical nature of the claimed is a method of controlling the transmit power in a cellular system mobile radio communications multiple access code division multiplexing (patent RU No. 2127951 C1, N IN 7/26, 04L 27/30, 1992). In the known method, the transmit power of the subscriber station control signal from the base station. When receiving a signal from each subscriber station with which a connection is established, the base station receiver measures the power of this signal. The measured signal strength is compared with the desired power level signal to the subscriber station. Form the team adjust the power and transmit it to the given subscriber station via a data transmission channel or a voice channel. In accordance with the power control from the base station to the subscriber station increases the sludge is reduced transmit power to a predetermined value, nominally 1 dB.

A command to adjust transmit power of the base station is transmitting at a relatively high velocity, equal to about one team for a millisecond. The baud rate command, control power must be high enough to track the Rayleigh fading in the receiving channel of the communication channel.

The disadvantage of the prototype is relatively low reliability of communication caused by not taking into account the constantly changing signal-to-noise at the location of the base station, and in some cases increase the load on the base station that exceeds its capacity.

The aim of the invention is to develop a method to control power AC mobile network code division of channels, ensuring higher reliability of mobile communication systems due to the dynamic power control of the transmitter, speakers, taking into account the noise level in the placement of base stations and information load on the BS, by assessing the quality of the communication channel and the priority network subscribers.

To achieve the formed target in a known method lies in the fact that the pre-set parameters of the communication channel, generate and transmit an information signal from subscriber stations (SS) to the base station (BS), compared to the BS parameters of the received information the local signal with the predefined communication channel, by comparing the results on the BS form a control signal to the power control AC, which is passed from the BS to the MSS, where in accordance with the received control signal to regulate the capacity of the AU, as parameters of the communication channel pre-set minimum kminand the maximum kmaxthe values of the error rate, minimumand maximumthresholds for the number of callers, assign each speaker priority level piwhere i=1, 2, ... is the number of priority levels. After the formation of the AC information signal further generate a test signal, combine it with information and transmit the combined signal to the BS, where the received combined signal to produce the test signal. Form on the BS test signal, which is compared with the received test signal, by comparing the results to calculate the error rate of the ktwhere t=1, 2, ... is the number of the speakers, which passed the test signal, comparing the value of the calculated error coefficient ktwith specified minimum kminand the maximum kmaxvalues of the error rate, and if kt<kmingenerate the control signal to reduce power AC, and if kt>kmin- to increase, and in the process of communication networks on which To measure the number of calls N callthat compared with a predefined minimumand maximumthresholds, ifcalls from subscriber stations with the lowest priority does not serve, as to this subscriber station transmits a busy signal.

Thanks to the new essential features due to continuous monitoring of the quality parameters of the communication channel (the error rate in the communication channel), accounting for varying signal-to-noise (noise) in place of BS, the load of the base station and the introduction of service priorities the proposed method can improve the reliability of mobile communications systems.

The analysis of the level of technology has allowed to establish that the analogues, characterized by a set of characteristics is identical for all features of the claimed technical solution is available, which indicates compliance of the device to the condition of patentability "novelty".

Search results known solutions in this and related areas of technology in order to identify characteristics that match the distinctive features of the prototype of the features of the declared object, showed that they do not follow explicitly from the prior art. Therefore, the claimed invention meets the condition of the patent is sposobnosti "inventive step".

The claimed method is illustrated by drawings:

figure 1 - cellular network;

figure 2 - timing diagram explaining the method of controlling the transmit power of the subscriber station.

The cellular system shown in figure 1, consists of a base station 1, the subscriber stations 2Nwhere N is the number of subscriber stations, and transmission path from the subscriber station to the base 3 and from the base station to the subscriber stations 4.

The method is as follows. Pre-set parameters characterizing the communication channel. As these parameters specify the maximum (kmax) and minimum (kmin) the coefficients of the error. In addition, the base station set the threshold number of callers - minimumand maximum. Each subscriber station is assigned a priority level piwhere i=1, 2, ... - the priority level. The assignment of priorities by the administrator of the communication network in accordance with the list provided to the subscriber of communication services, and for departmental mobile networks in accordance with the position of the subscriber. The database with the assigned subscribers priorities is at the base station.

At the subscriber stations simultaneously form information (figa) and test (Phi is b) signals. Then unite them into one common group flow (pigv). Methods of combining known and described, for example, in the book Waheguru, Sveglia "Foreign communication" (SPb.: YOU, 2004, s, 244). United multicast flow is passed from the subscriber stations to the base.

At the base station receive the transferred subscriber station group signal (high) and produce from it a test signal (figd). Methods of extraction are known and described, for example, in the book Waheguru, Sveglia "Foreign communication" (SPb.: YOU, 2004, s, s). At the base station generate a test signal that is identical to the test (fige). Formation is carried out according to the same rules as for the test Segal on subscriber stations.

Passed the test signal is compared with the generated test and produce the error signal (Figi). Calculate the current error rate of the ktwhere t=1, 2, ... is the number of the subscriber stations, which adopted a test signal, which consider the number of error signals per unit time (for example 1). Compare it with the specified maximum (kmax) and minimum (kmin) coefficients of the error.

If the inequality kt<kminon the base station generate the control signal to reduce the power of the transmitter of the subscriber station. If there is inequality kt> kminon the base station generate the control signal to increase the power of the transmitter of the subscriber station. The generated control signal is passed from the base station to the subscriber. At the subscriber station shall receive the control signal, and then adjust the transmit power of the subscriber station in accordance with adopted from the base station command.

At the base station continuously measures the amount of incoming calls Ncallper unit of time (information load). If the number of incoming calls exceeds the pre-determined thresholdi.e is the inequalitythe base station suspends the service subscriber stations with the lowest priority. At the same time from the base station in the direction of subscriber stations with the lowest priority transmit a busy signal. After going to be the inequalitythe base station newly starts to serve all subscriber stations. As a result, by removing the base station information of the load coming from subscribers with the lowest priority, reliability of customer service with the highest priority.

The method of controlling the power of the subscriber station is th communication network, code division multiplexing, namely, that the pre-set parameters of the communication channel, generate and transmit an information signal from subscriber stations (SS) to the base station (BS), compared to the BS parameters of the received information signal with a predefined communication channel, by comparing the results on the BS form a control signal to the power control AC, which is passed from the BS to the MSS, where in accordance with the received control signal to regulate the AC power, wherein the quality parameter of the communication channel pre-set minimum kminand the maximum kmaxthe values of the error rate, minimumand maximumthresholds for the number of callers, assign each speaker priority level piwhere i=1, 2, ... the number of the priority level, after the formation of the AC information signal further generate a test signal, combine it with information and transmit the combined signal to the BS, where the received combined signal to produce a test signal, is formed on the BS test signal, a similar test, which is compared with the received test signal, by comparing the results to calculate the error rate of the ktwhere t=1, 2, ... the number of speakers, which passed the test signal, ravnivat value of the calculated error coefficient k twith specified minimum kminand the maximum kmaxvalues of the error rate, when kt<kmingenerate the control signal to reduce power AC, and if kt>kmin- to increase, and in the process of communication networks on the BS measures the number of calls Ncallthat compared with a predefined minimumand maximumthresholds, ifcalls from the speakers with the lowest priority service and pass it the "busy"signal.



 

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